Patent Document 1 discloses a compressed air energy storage system, which accumulates, in a compressed gas accumulation device, a compressed gas from which heat is recovered by a heat exchanger arranged on a downstream of a compressor, and heats the gas taken out from the accumulation device by the recovered heat, thereby supplying the gas to a power generation device.
In this system, the heat of the compressed gas from the compressor is recovered by a high-temperature heat exchanger and a low-temperature heat exchanger. However, in either case, the heat is recovered only from the same compressed gas and heat recovery from heat sources other than the compressed gas is not considered.